1. Field of the Invention
The present invention relates generally to digital broadcasting, and more particularly to an apparatus and a method capable of receiving digital broadcasting without image discontinuity during channel switching.
2. Description of the Related Art
Digital broadcasting, in particular, digital multimedia broadcasting (DMB) utilizing a system E scheme of an international telecommunication union (ITU) proposes convolutional interleaving/deinterleavirig. According to the convolutional interleaving, a DMB transmitter temporarily stores several input bits, delays the input bits for a predetermined period of time and outputs the delayed input bits when transmitting broadcasting data. Consequently, several bits delayed and output are interleaved between two bits adjacent to each other at the time of input. Accordingly, the DMB transmitter obtains a data stream having a sequence different from an input sequence through an interleaving and transmits the interleaved data stream.
A DMB receiver deinterleaves the interleaved data stream received from the DMB transmitter and restores the data stream to an original input bit sequence. When a continuous burst error has occurred in a portion of the interleaved data stream transmitted from the DMB transmitter, the data stream, having been restored to the original input bit sequence through the deinterleaving process, has a random error changed from the burst error. Accordingly, a viterbi decoder of the DMB receiver can effectively perform an error correction.
When a broadcasting channel is switched, the DMB transmitter fills buffers of a deinterleaver for a changed broadcasting channel (i.e., performs deinterleaving) and then displays the changed broadcasting channel. Accordingly, whenever a broadcasting channel is switched, a period of time is required for the buffer of the deinterleaver to empty and then fill. In the conventional DMB receiver, a period of time from 0.264 seconds at minimum to 6.514 seconds may be required for a deinterleaver buffering.
Additionally, when considering a period of time for which the DMB receiver divides the deinterleaved and error-corrected broadcasting data into audio data and video data and processes the audio data and video data, the DMB receiver does not display anything for more than several seconds. Accordingly, a user's viewing is interrupted with image discontinuity such as blue screen every time prior to watching other broadcasting channels.